In the field of dental goods and materials, there have recently been developed various adhesives having excellent adhesiveness to a tooth, especially to a dentinal portion thereof. Used as adhesive components in such adhesives as referred to above are polymerizable monomers having acid groups in the molecule. These polymerizable monomers which are known, per se, include (meth)acrylate monomers such as those having in the molecule phosphoric acid diester groups (Japanese Patent L-O-P Publn. No. 113089/1977), phosphoric acid monoester groups (Japanese Patent L-O-P Publn. No. 21607/1983), carboxyl group or acid anhydride groups (Japanese Patent L-O-P Publn. No. 11149/1979) and acid halide groups (Japanese Patent L-O-P Publn. No. 151607/1982).
However, even in the adhesives containing such adhesive monomers as mentioned above, a further improvement is desired in that when a dental restorative material (filling material, metal, etc.) is applied to a tooth, a further improved adhesion between the tooth and material is obtained and, moreover, no gap is formed in the marginal gap between the tooth and material thus united.